Bending machine



Feb., 2e, 1924. l 1,485,313-

J. W. TAYLOR BENDING MACHINE Filed June 2l. 1921 2 Sheets-Sheet l Feb. 26, 1924;'

1,485.313 f J. w. TAYLOR v BENDING MACHINE yFiled une g1. 1921 2 Sheets-sheet- 2 Patentes ses. as, reas.

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Banniere amounts.

Application filed June 21, 1921. Serial No. 479,354u

To all whom t may concern.'

Be it lrnoWn/thatl, JOHN WALLACE TAY- Los, a citizen of the United States, and residing at Cleveland, county of Cuyahoga., State of Ohio, have invented certain new and useful Improvements in Bending Machines, of which the following is a specification.

The present invention relates to machines for curving metal articles and particularly to mandrels for machines used in curving the individual leaves of built-up leaf s rin of the curved cantilever' or semi-e liptic type.

ln shaping the leaves of built-up curved leaf springs the leaves Vare received from the furnace in a highly heated condition and substantially straight and are then curved in a press While hot, to the desired ccniguration and immediately "thereafter plunged into or quenched in a fluid cooling medium such as Water or oil, generally the latter. The leaf springs may of course be built-up of straight leaves but are usually curved into the well known curvedcantilever or semi-elliptic forni for mechanical reasons, depending upon the use to which they are to be ut. For instance, vehicle springs are usua ly semi-elliptic to provide the necessaryT clearance between the vehicle axles and the vehicle jbody, and generally two seini-elliptic springs are joined to form a full elliptic spring, to provide additional clearance. p

n order that the springs, Whether strlaig'ht or curved, may be made as light as possible for a given strength they are formed substantially as beams of uniform strength, the thickness of the spring gradually increasing from the end or ends bearing the loads toward the point of support. For a number of reasons it is not desired to form such spi-ings of a single member which gradually increases in thickness toward the point of support but they are built-up in the well known manner, of a plurality of superposed individual leaves of different lengths which are secured together at one point. In the# ory, the spring being designed as a beam 'of uniform strength, each leaf will be equally stressed when the spring is loaded and furthermore the stress throughout the lengthl of each leaf of the spring Will be the same under any given load. Therefore, when such a spring is loaded and liexes under the load the curve which it assumes will be the therefore it has been are `of a circle inasmuch as the unit stress from end to end .of the spring will be the saine and hence the deformation-of eacli junit length will be the same, and each unit length stretching the same amount or contiacting the sameaniount, as the case may be, causes the curve to be circular, provided of course, that before loadin the s ring was either straight or curved a ong t e arc of a circle. v In the manufacture of curved leaf springs thepractice to form j the individual leaves as arcs' of circles, the radius depending of course on the size of the spring and upon the use to which it is to be put. A number of types of machines have been heretofore designed or suggested for* curving the individual leaves of such springs. One of such machines contemplates the use' of a flexible plate adjustably supported at a number of points so that its radius of curvature may be varied at will, this plate constituting the special form or mandrel upon which the leaf spring is shaped and having ahead or plunger assoc iated therewith for bending the leaf placed on the mandrel so that it conforms to the shape thereof. ln another type of machine heretofore employed a plurality of aligned adjustable pins have been provided the pins being closely arranged and together constituting the mandrel. In each of thesel types much time isv lost when it is desired to change the radius to which spring leaves 90 are to be bent, it being necessary to individually adjust the separate pins and repeatedly check them to ascertain whether or not they are roperly positioned. Solid mandrels have li course entirely non-adjustable, and also in some cases sample spring plates? have been rigidly supported and used as mandrels.

The object of the present invention is to improve upon such machines heretofore einployed in the curvature of leaf springs or similar metal articles by providin an iinproved mandrel which may be adj'usted to different radii of curvature quiclrly, and by making a single adjustment in the case of la cantilever spring, or two adjustments onl in the case of the semi-elliptic spring, al other adjustments being avoided.. To this end l employ as a mandrel a built-u `leaf spring either of cantilever'or semi-e liptic type the spring being supported at its heavy y end in the case of the cantilever and loaded een used but these are of .being for t at its light end, or supported at its middle point in the case of the semi-elliptic type and loaded at each end. By varying the loadsthe radius of curvature of the mandrel mayV be changed at will, the curve however remaining practically the arc of a true circle at all times.

Inr the following specification and in the accompanying drawings'the invention will be disclosed, several diiferent embodiments .being described and illustrated. In the drawings: n y y Figure l is a front elevation of a press for curvin leaf springs, the mandrel shown die purpose of forming springs of the semi-elliptic type;

Figs. 2, 3 and 4 illustrate diagrammatically mandrels which may be substituted for vthe mandrel of Fig. 1, and which, when loaded and supported at the points indicated, will curve uniformly, that is along circular arcs;

Fi 5 illustrates diagrammatically the man rel illustrated in Fig. 1;

Fi 6 illustrates Vdiagrarnmatically the man el for a cantilever'spring showing the method of supporting and loading the same; Fig. 7 shows a mandrel which may be used in place of the mandrel of Fig. 1;

Fig. 8 shows a mandrel adjusted to obtain areverse curve; and

'Fi 9 is a section on line 9 9 of Fig. 1.

Re erring to Fig. 1 it will be seen that the machine comprises-essentially a fluid,

pressure cylinder 10 having a piston 11 therein which is connected by the piston rod 12 to a transversely extending head 13 so that this head is reciprocated vertically with the piston as uid under pressure is intro# duced into the ends of the cylinder alternatel To the under side ,of member 13 are rigid y secured the spaced leaf s ring mem- L ing this movement'an keeping the table 16 above the level of the oil.

Supported on table 16 is a mandrel 22 which in the form shown comprises a semielliptic leaf spring, this mandrel being supported at its center by member 23 and hav- 'ing its ends pivotally connected to vertical threaded bolts 24 which extend downwardly through slots in the table 16 and are provided with adjust' nuts 25. By adjusting theends of the sprin mandrel its configura- Ensems tion may be. changed and if the loads iinposed upon the ends by-bolts 24 vare equal,

the curvature of the mandrel will always be 'along the circumference of a true circle; By merely adjusting bolts 24 therefore the mandrel may be caused to assume curves of A' different radii and it is unnecessary tocheck the position of the mandrel at any. oints between its center and ends, since it a ways is truly circular. If the mandrefwererigidly held at its lcenter, as shownin 8,

unequal loads may be applied to its en s so descend and forcibly curve the spring leaf 26 to conform to the shape of the mandrel, the band 15 curving until it lies parallel to the mandrel. Vhen the heated leaf has been given the desired curvature the movement of the piston is continued, to force the mandrel, work, and flexible member 15 beneath the surface of the oil to quench the leaf while forcibly held to the proper degree of curvature. After being held in the oill a sufficient length of time, the piston is lifted and the work removed, after which the cycle may be repeated with a new spring leaf.

Instead of the mandrel shown in Fig. 1 the cantilever mandrel illustrated diagrammatically in Fig. 6 ma be utilized, or the mandrels illustrated iagrammatically in Figs.I 2, 3 and 4, these diagrams illustrating Various types of simple beams of uniform strength.

' It kwill be obvious to one skilled in the art that the invention may be embodied in still other forms and that the design and arrangement of parts may be changed without departing therefrom.

Throughout the specification and claims the word load isused to designate the force applied to the mandrel to effect the adjustment thereof. The mandrel may be loaded in various ways to effect the desired adjustments, as will be evident.

What is claimed is:

l. A bending machine includin in combination, a ilexlble mandrel, space supporting elements for the mandrel, said elements being relativel adjustable so that the mandrel may be exed to different degrees' of curvature, the mandrel so diminishing in cross section from one supporting element toward the adjacent element that the portion thereof between said supports automatically assumes a circular curve for all adjustments of the supporting means.

y madera '2. A. bending machine including in cembinaton, la flexible mandreb spaced Supportingr elements for said mandrel one ol' Said elements being stationary and an other adjustable relatively thereto so that the mandrel maybe flexed to different degrees of curvature, the mandrel so diminishing in cross section from one supporting element toward the other element that the portion thereof between said supports automatically assumes a circular curve for all adjustments of the supporting:r means.

3. A bending machine including in com bination, an elongated flexible mandrel., three supporting elements engaging said mandrel at different points along its length one or moreof said 'elinents being:r adjustable so that the mandrel may be flexed vto dill"erent degrees of curvature, the mandrel so diminishing in cross section from the inter-4 mediate element toward each* of the outer supportlng elements that each portion thereof between the intermediate element and an outer supporting element automatically assumes a circular curve for all relative adjustments of said intermediate and outer elements.

l. A bending machine including in combination, an elongated` flexible mandrel, supporting means for saidemandrel'including three supporting'elements oneoffsaid elements rigidly supportingthe mandrelat its middle andthe other elements connected to the ends of the mandrel respectively and being adjustable relatively to the intermediate support, and said mandrel so diminishing in cross vsection from said stationary central support to each of said adjustable supports that the mandrel automatically assumes a circular curve for all adjustments ot the supporting means.

In testimony whereof I hereunto affix my signature.

JOHN WALLACE TAYLOR. 

